I just changed from Ortho-Tri-Cyclen Lo to Tri- Previfem

I was on OTCL for about a year, and the last 4 months I've been getting my period for 14 days. So my GYN/OB switched me to Tri-Previfem because of the "slightly" higher dose of hormones....my biggest fear is gaining weight on it. I was reading horror stories. One story said she was a vegetarian, ate extremely healthy and worked out daily (which I am/do) and the first two months of being on it, she gained weight. I didn't gain weight when I began OTCL. And when I was on LoEstrin24Fe. I actually lost a bit of weight....so do you think I'd gain anything if my last two didn't?